This invention pertains to an assembly for the diffusion of a fuel vapor with an oxidizing agent so as to produce a combustible mixture and, more particularly, to such a device functioning as a carburetor for introducing a fuel/air vapor mixture into an induction system of an internal combustion engine.
The burgeoning interest in fuel economy of known internal combustion engines has led to critical reevaluations of the internal combustion engine, and more particularly, to the associated fuel systems and/or components used to present a combustible mixture thereto. Normally, such fuel systems have included a carburetor which sprays liquid fuel into an air stream so as to break down the fuel into a plurality of droplets striving to approach a vaporized state so as to be susceptible for subsequent combustion.
Prior evaluations of known carburetors have spawned a plurality of devices and/or improvements associated therewith which were designed to enhance the dispersion of the fuel droplets into increasingly finer particles, this process commonly referred to as atomization of the fuel. These devices have provided for atomization at various stages prior to fuel entry into the associated internal combustion system.
However, such evaluations of atomization of the liquid fuel have failed to appreciate that only those molecules at the exterior surface of the fuel droplet are in a position to obtain sufficient energy to escape the fuel droplet so as to be able to diffuse with the surrounding air.
If the surrounding air does not contain sufficient heat to evaporate all of the liquid droplet, a mixture of gaseous air, gaseous fuel and fuel droplets results. Such a mixture can be considered a saturated vapor mixture which needs further heat energy for complete evaporation. However, attempts to add the required external heat without regards to a mixture temperature limit have caused the fuel mixture to rise to a temperature at which preignition and subsequent detonation can occur as well as a reduction in the density of the composite fuel/air mixture ratio leading to a reduction in h.p. But if the air/fuel mixture is cooled during this evaporation process, the existence of a critical temperature must be considered below which it is not possible to evaporate all the fuel droplets suspended in the air.
After such a mixture is introduced into the internal combustion system, combustion will occur with part of the energy released during the combustion process absorbed into the evaporation of the remaining aerosol droplets of the fuel. However, insufficient oxygen is available to completely burn the incoming mixture which causes the remaining fuel droplets to exit the combustion chamber as unburned hydrocarbons in the exhaust system, which may lead to undesirable combustion therein with resulting emissions.
Although it is possible to sufficiently evaporate liquid engine fuels into the surrounding air given a sufficiently extended time for such process to occur, it is apparent that such time is not available in the internal combustion engine as there is very little time between presentation of the fuel and combustion. To overcome such a short time span much more fuel is presented for combination with the incoming air than is actually needed to form an optimal combustible mixture. Accordingly, it can be seen that most of the fuel is now wasted in the operation of the internal combustion engine.
It has been recently recognized that the liquid fuel must be put into a complete vaporized state in order to present the greatest degree of separation of molecules in each fuel droplet so as to increase the rate of reaction with the oxidizing airstream. However, problems have arisen in known structures attempting to implement this concept, including the above-mentioned overheating problems and more importantly the failure to properly deliver the fuel/air mixture to the internal combustion system in accordance with known parameters associated therewith. Accordingly, the manner of vaporization of the fuel, the diffusion of the vaporized fuel with the oxidizing agent and, more particularly, the introduction of such a mixture to the internal combustion engine must be addressed.
This invention provides a carburetor-type device for association with an internal combustion engine which efficiently heats the liquid fuel at a safe temperature to present a vapor state; superheats the vapor at a safe operating temperature to present a relatively dry gas; provides means for regulating the flow rate of this dry vapor, relative to the rate of flow of the incoming airstream being drawn into the internal combustion engine, for diffusion therewith; and provides means for controlling the fuel/air ratio mixture delivered into the internal combustion system.